The use of catheters to study and correct problems in the human circulatory system is known. Specifically, if any of the heart chambers, heart valves, arteries, veins or capillaries of a patient are malfunctioning due to birth defects, restrictions such as atherosclerotic plaque build-up or other causes or are deteriorated from an aneurism or other disease, then a physician may need to examiner the heart and associated network of blood vessels. Catheters are known to be used for such angiographic examinations as well as for carrying out corrective procedures such as ablation.
Angiography is a procedure used to detect and treat abnormalities or restrictions in blood vessels. During angiography, radiographic images of the vascular structure are obtained by injecting contrast material through a catheter into a vein or artery. The contrast material fills the vein or arteries and x-ray images are taken of the body region under examination. The x-rays are absorbed by the contrast material (also known as radiographic contrast material or solution) and the resulting x-rays produce a radiographic outline or image of the blood vessels under examination.
The angiographic images are useful for diagnostic purposes as well as for angioplasty or ablation procedures where a balloon is inserted into a vein and/or artery and is subsequently inflated to open a restriction caused by atherosclerotic plaque build-up.
During an angiographic procedure, a catheter is placed into a vein or an artery. The catheter is also connected, at its proximal end, to either a manual or automatic contrast injection mechanism. The contrast injection mechanism injects the contrast solution into the catheter. Often, the catheter is also in fluid communication with a pressure transducer which is used to monitor the pressure in the vessel or artery under examination.
The pressure transducer and contrast injection mechanism are typically connected to the catheter through a manifold. The manifold includes a valve which enables the physician to isolate the pressure transducer during the injection of the contrast solution. The isolation of the pressure transducer is necessary because the transducer can be damaged by a pressure increase caused by the injection. Specifically, many pressure transducers can be damaged if they are subjected to a pressure of over 125 psig. Because even a hand-held syringe can generate pressures of 200 psig or more, the isolation of the pressure transducer is essential in order to avoid transducer failure.
One solution to this problem is provided by some currently available manifolds which do not allow the contrast injection to be made while the pressure transducer is in communication with the catheter. Specifically, a stopcock configuration is provided which either allows the pressure transducer to be in fluid communication with the catheter or the contrast injection mechanism to be in fluid communication with the catheter, but not both. Typically, the stopcock handle must be turned manually to switch between the two positions.
The problem associated with these currently available manifolds is that the physician often forgets to turn the stopcock back to the position where the pressure transducer is in fluid communication with the catheter. As a result, the monitoring of the vessel or artery is interrupted for time periods longer than necessary. The monitoring of the vessel or artery pressure is important during almost any vascular procedure. Accordingly, when the physician fails to turn the stopcock handle, other members of the medical team must interrupt the physician and tell him or her to turn it back on which may cause an unnecessary distraction to the physician during a delicate medical procedure.
Accordingly, there is a need for an improved valve or manifold device which can automatically isolate the pressure transducer from the catheter and contrast injection mechanism during the injection of the contrast solution.